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AT/MT identifier, and gas guzzle?


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Sup all....havent given you an update on the swap in awhile....its about 95% done....of course there is something new i want to do everyday so it will never be at 100%

 

Anyway any of you gurus out there want to enlighten me on all the functions of the AT/MT identifier pin...i have gathered it makes the mixture more or less rich...and im guessing the ECU is then looking for diffrent volatges on the nuetral pin etc....any other benifits....what about leaving it on AT any benifits disadvantages??

 

Also im getting about 210 miles out of a tank of gas....city driving mostly....seems a little low..even for a suby...any suggestions?

 

thanks

 

Cory

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You need to make sure that identifiy pin is properly snipped or grounded.

 

That pin tells the ECU to adjust timing as well as fueling, and when to do it. Also, the neutral switch operation is backwards for the AT & MT setups. So if you leave it so the ECU thinks the car is AT, when it's MT. The ECU will think the car is in gear when it's actually in neutral, and vice versa.

 

It should be pretty obvious to know whether the pin is wired properly. If it's still setup for AT, the rpms should raise up when you move the gear shifter in Neutral, but then drop back down when you put it in gear.

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We wired the clutch pedal through a relay to the B11? connector pins 10 and 11 or 12 or something...so when i push the clutch in, it completes the circut telling the car it is in neutral and when the clutch is up, it is in gear....the rpms do go up and down when i push the clutch in and out...should i do something diffrently?

 

also, we grounded the AT/MT pin so that we get a 0V reading on the chassis...no wire coming out of it....it was 5v until grounded.....

 

on a funny note, i wired up the reverse light, no problem just used my ohm meter tested a couple leads found the ones hooked to the connector for the AT and \boom it worked....well the next day im driving to work and one of my coworkers says...your reverse lights were on when you were going by...so i looked no lights?? what?? turns out i had wired it to the nuetral sensor and it was completing the circuit every time i put it in gear =0)

 

cory

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You've got some wiring issues you need to take care of.

 

I'm assuming you've read over my write-up. You need to wire everything similar to my setup.

 

The neutral switch needs to be wired to the ECU's neutral pin, not the clutch switch.

 

So the MT/AT ident pin did not have a wire hooked up to it? If it didn't and you grounded it, it "should" be setup properly. What year is your impreza again?

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The neutral switch needs to be wired to the ECU's neutral pin, not the clutch switch.

Ok here is the story, in the beginning just to get the car to start, we wired two leads on the B11? (one in the engine compartment that the auto was connected to) connector this just fooled the car into thinking it was in neutral. then we wired up the same leads but this time (to make a long story short) basically wired it so when the clutch is pushed in it shorts these two leads and when it is out the circut is open.....should i wire the neutral switch from the transmission to the ECU? if so how?

 

So the MT/AT ident pin did not have a wire hooked up to it? If it didn't and you grounded it, it "should" be setup properly. What year is your impreza again?

It had no wire coming out of it...we grounded it and got a 0V when grounded to chasis...that should be right...i have a 1997 impreza go here to see the ECU guide i used

 

http://www.ravensblade-impreza.com/modifications/misc/wiring/wiring.html

 

Thanks again josh i really appreciate all of your help

 

Cory

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Ok here is the story, in the beginning just to get the car to start, we wired two leads on the B11? (one in the engine compartment that the auto was connected to) connector this just fooled the car into thinking it was in neutral. then we wired up the same leads but this time (to make a long story short) basically wired it so when the clutch is pushed in it shorts these two leads and when it is out the circut is open.....should i wire the neutral switch from the transmission to the ECU? if so how?

Yes you need to connect the neutral switch to the ECU. If you route the MT's neutral switch wiring through the existing AT's neutral switch wiring you'll be good. The only issue with this is, on the older cars you got backfeeding of power through the AT lights on the dash. The newer cars used a different setup, and this wasn't a problem. However, without an electrical diagram for your car, I couldn't really tell you. for sure. You could try just hooking it up like I mentioned. If the neutral indicator on your dash comes on, then you'll need to do some tweaking.

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Yes you need to connect the neutral switch to the ECU. If you route the MT's neutral switch wiring through the existing AT's neutral switch wiring you'll be good.

by existing AT wiring, you mean the connector in the engine compartment?

 

The only issue with this is, on the older cars you got backfeeding of power through the AT lights on the dash. The newer cars used a different setup, and this wasn't a problem. However, without an electrical diagram for your car, I couldn't really tell you. for sure. You could try just hooking it up like I mentioned. If the neutral indicator on your dash comes on, then you'll need to do some tweaking.

No dash indicators so this isnt a problem

 

thanks

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by existing AT wiring, you mean the connector in the engine compartment?

 

 

No dash indicators so this isnt a problem

 

thanks

Yup the connector in the engine compartment. It should be the same pins as my car. What I'd do is check the continuity between the pin on the engine connector and the neutral switch pin at the ECU just to verify the pin outs are the same.

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Yup the connector in the engine compartment. It should be the same pins as my car. What I'd do is check the continuity between the pin on the engine connector and the neutral switch pin at the ECU just to verify the pin outs are the same.

Thanks josh...ill let you know how it works out

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